Analysis of dipole noise level characteristics of NACA0015 hydrofoil under different working conditions

Abstract

In this paper, the flow field around NACA0015 hydrofoil is calculated under the condition of two-phase cavitating flow to provide a theoretical guidance for reducing the cavitation noise. A modified turbulence model coupled with the Zwart cavitation model is used to calculate the flow field. According to the computed sound source data, the dipole sound pressure distribution diagrams for the extremely short time and the complete time around the hydrofoil under different working conditions are obtained. The sound pressure distribution and the sound pressure amplitude are analyzed in detail. In addition, the field points around the hydrofoil are selected to generate the corresponding frequency response function curves, which are analyzed from the aspects of the trend, the variation and the extreme value. The results show that the dipole characteristics are gradually diminished and finally disappear with the increase of the frequency. At the frequency of the vapor volume fraction fluctuation, the noise level at the field point will have an extreme value.